The present invention relates generally to boring tubes.
In particular it relates to a boring tube which has at least one tubular base body with a longitudinal passage.
Boring tubes after producing a bore are used as a lost tool of the type of a rock anchor, and they are known in many forms. They must be suitable not only for producing a bore, but also for unobjectionable, particularly central guidance of the boring tube as well as for introduction of a mortar suspension or a similar, hardenable medium. The production of the bore requires the supply of a suitable rinsing medium which depends on the property of the surrounding rock or ground and is discharged in direction toward the bore opening during the boring progress. Due to the central guidance of the tube, in the hardened condition an all side uniform covering of the boring tube by the mortar suspension is obtained for protecting the boring tube from corrosive action. An introduction of the mortar suspension is conventionally performed through the boring tube located in the bore hole. The mortar is discharged preferably in the region of the boring crown and the bore hole is filled in a rearward direction, or in other words, in direction toward the bore hole mouth.
The central guidance of a boring tube with a spacer is disclosed in the non-published patent application P 41 28 154.3 of the applicant. The spacer is formed by several round iron members which are welded on the connecting sleeve provided for coupling of two boring tubes, and the length of the round iron members corresponds to the length of the respective collar.